1. Field of the Invention
This invention relates to electrical connectors, and more particularly to a shielded electrical connector including data bus coupling circuitry.
2. Description of Related Art
A data bus coupler is an electrical connector which permits splitting of data signals without attenuation of the signal strength. The data bus typically includes a single, twisted, pair of wires and a cable shield which protects transmitted data from magnetic and electrostatic interference. The coupler typically includes a bus line which connects an input contact to an output contact, and a number of branch or stub contacts tapped into the bus line via transformers. The resulting multiplexed data bus coupler enables the use of smaller and lighter twinaxial cables instead of complicated, heavy and dedicated cabling. Desirable qualities in a data bus coupler are that the coupler be compact, lightweight, electromagnetically sealed, and able to withstand severe environmental conditions.
One such data bus coupler is disclosed in U.S. Pat. No. 4,720,155. The coupler of U.S. Pat. No. 4,720,155 includes a metallic shell, an apertured ground plate to connect the shields of the contacts to the shell, a dielectric contact retention member, and a circuit board which carries a transformer and isolation resistors. The ground plate fits between the main housing and a rear can enclosure which encloses the circuit board.
The coupler disclosed in U.S. Pat. No. 4,720,155 provides a compact and effectively shielded structure. However, for many applications, it would be desirable to reduce even further the weight, number of parts, and size of such a coupler, without reducing its shielding effectiveness.